Admittance of rectangular waveguide of slot array measured

The serial feed waveguide H-plane slot array antenna is a widely used antenna type. The relationship between the waveguide slot conductance and the geometrical dimensions of the slot is the foundation for designing this type of antenna and the frequency characteristics of the slot admittance is an indispensable basis for analyzing the antenna's frequency characteristics. Although the formulas for theoretical analysis can be applied in designing a waveguide slot array antenna, there are some irregularities between the results obtained and the actual situation; therefore, before design, the conductance of the waveguide antenna is measured. Because the conductance of a single slot is rather small, it is difficult to measure accurately and in addition, there is coupling between slots, thus people generally measure the slot conductance of many slots in the array. To analyze and predict the frequency characteristics of a serial feed waveguide H-plane slot array antenna and improve the antenna's broad-band performance, an easy, computer-aided method of measuring the admittance frequency characteristics in a slotted array is proposed the results of measurement are presented. From the results it can be seen that the frequency characteristics of slot admittance are regular.